As reported in the Evening Times last week, the mystery man's picture was found among piles of rubbish in the loft of a house in Shawlands.
Home owner Louise Andrew took it to the Glasgow Police Museum in a bid to uncover the man's identity.
After reading our story, quantity surveyor Stuart Bass immediately recognised the officer as his great-grandfather John Maclean.
Mr Maclean served as a lieutenant in the City of Glasgow Police, the equivalent rank of a modern-day chief inspector.
His picture, along with a second photograph showing him and other members of his family, was found by Ms Andrew when she was clearing out her attic.
Mr Bass, 49, from Stewart Drive, Clarkston, said: "I recognised the picture right away.
"My grandfather and two great-aunts, the young girls in the family photograph, lived in Randolph Drive in Clarkston.
"When the aunts died in 1993 I took these photos to our house. We moved to Woodstock Avenue for a few years and they must have got lost when we moved again.
"The picture of the policeman was familiar but the one that I recognised was the family portrait.
"I had been looking for it, because my oldest son Michael closely resembles my grandfather, who is the boy in the picture in shorts."
Mr Bass said he had spoken to the curator of the Glasgow Police Museum, Alastair Dinsmor, about his great-grandfather John Maclean.
He said: "My grandfather also became a police inspector and Alastair is going to track down some background details on them."
The picture of Mr Maclean is going to the museum.
Mr Dinsmor said: "I've already found out some information about John Maclean. He joined in 1891 and worked his way up to lieutenant.
"He got six commendations from the chief constable, and once received seven shillings for catching two men shebeening - selling alcohol illegally."
Ms Andrew said she was delighted that the mystery had been solved.
She added: "I thought they were lovely photos and probably meant a great deal to whoever had left them behind."